Field
This disclosure is generally related to distribution of digital content. More specifically, this disclosure is related to a method and system for adjusting entries in a forwarding information base in a content centric network.
Related Art
The proliferation of the Internet and e-commerce continues to create a vast amount of digital content. Content-centric network (CCN) architectures have been designed to facilitate accessing and processing such digital content. A CCN includes entities, or nodes, such as network clients, forwarders (e.g., routers), and content producers, which communicate with each other by sending interest packets for various content items and receiving content object packets in return. CCN interests and content objects are identified by their unique names, which are typically hierarchically structured variable length identifiers (HSVLI). An HSVLI can include contiguous name components ordered from a most general level to a most specific level. A CCN forwarder (e.g., an intermediate node or a router) can receive and forward interests and content objects based on their names. The forwarder can implement a local forwarding strategy based on three data structures: a pending interest table (PIT), which records all interests that the router has forwarded but not yet satisfied; a forwarding information base (FIB), which is a routing table that maps name prefixes to outgoing interfaces; and a content store (CS), which is a temporary cache of data packets received by the forwarder.
The FIB can be populated by a name-prefix based routing protocol, and a FIB entry may include a list of multiple outgoing interfaces for a name prefix. Given an interest with a name prefix that has multiple outgoing interfaces in the corresponding FIB entry, the forwarder can determine how to forward the interest. For example, the forwarder may forward the interest to the interfaces in sequence, by forwarding the interest to the first listed interface and waiting for a response. If the forwarder receives an interest return message (indicating an upstream error or failure), or a timeout occurs, the forwarder may forward the interest to the next listed outgoing interface. However, this sequential or “serial” strategy (similar to a depth-first network traversal) may lead to inefficiencies in the network. The forwarder may instead forward the interest as a multicast message, by forwarding the interest in parallel to all listed interfaces. However, this may introduce additional and unnecessary traffic in the network, which may also lead to inefficiencies in the network.
While a CCN brings many desired features to a network, some issues remain unsolved for a forwarder in determining a forwarding strategy for forwarding interests with multiple outgoing interfaces listed in the FIB.